3800 V6 Bottom End

[sciphi]

Here are some pictures of my Buick's 3800 V6 with 87k miles on it while changing the oil pan gasket earlier today. I'd never seen the guts of an engine before. It was pretty neat to see. A little nerve-wracking to work around, too.

Long shot:

Pickup screen:

See if you can catch the reflection on the cylinder wall.

The undersides of the pistons are very clean:

Some casting numbers:

Slightly removed:

The signs of a leaking pan gasket that started all this:

 

[Bill in Utah]

THANKS for the photos!

 

[Trav]

Any rot on the pan? The internals look nice and clean.

 

[sciphi]

The pan is rot-free thanks to the leaking gasket providing a oil shield, lol!

There was a tiny bit of sludge at each end of the pan. Nothing worth taking a picture of. It wiped out nicely with a paper towel.

 

[Nick R]

I wasn't aware that the 3800 was a 3 crank throw design.

 

[ItsuMitsubishi]

Nick, you're were right the first time, it's an optical illusion! The pins are indeed split.

 

[beast3300]

Looks good, did you RTV both sides of the gasket?

 

[sciphi]

Originally Posted By: beast3300
Looks good, did you RTV both sides of the gasket?


No, only in the corners. The directions specifically said not to RTV the gasket except in the corners, where the block meets the front and rear covers.

 

[Shannow]

Originally Posted By: Nick R
I wasn't aware that the 3800 was a 3 crank throw design.


There was an odd fire single crank throw early on in it's life (from being a shortened 215 Buick V-8 that became the Rover/TVR/Leyland V-8), but became a split throw even fire a long time ago.

 

[ekpolk]

What oil(s) have you been using? Thanks for taking the time to post up those pics.

 

[panthermike]

Originally Posted By: ekpolk
What oil(s) have you been using? Thanks for taking the time to post up those pics.


Taken from his other thread;

Mostly Syn oils @ 7500-9000 mile OCI's(Synpower, Q Torque Power, Schaeffer's 7000) and two ARX cleanings. Currently has Castrol Edge.

 

[Lethal1ty17]

looks very clean, the undersides of the pistons look a tad dirty but i guess they dont get much oil flow

 

[xxch4osxx]

Originally Posted By: Lethal1ty17
looks very clean, the undersides of the pistons look a tad dirty but i guess they dont get much oil flow
They also get extremely hot, so there tends to be some deposits build there.

 

[sciphi]

Still fine a week later. The motor seems to like the Edge+3 oz. ARX.

Seeing the motor with that light coat of varnish was very nice. Especially since the first 30k under previous owners didn't get that many oil changes. I know the maintenance history from 16k to 30k didn't see that many oil changes. When I got the car with 30k miles on it in late 2007 the oil was 2-3 years old, with maybe 500 miles of short trips in there. The first or second trip with it was to get the oil changed.

 

[caprice_2nv]

I think that's pretty close to what my mid 70's 350 Olds looked like inside when I was changing all the gaskets on it. It's probably even cleaner now.

 

[Lethal1ty17]

Originally Posted By: xxch4osxx
Originally Posted By: Lethal1ty17
looks very clean, the undersides of the pistons look a tad dirty but i guess they dont get much oil flow
They also get extremely hot, so there tends to be some deposits build there.


just out of curiosity, how hot does a piston get. i know its exposed to the flame front and pressure so its gotta be pretty warm. just outta curiosity.

 

[xxch4osxx]

Not sure about that, im guessing whatever the temp of combustion is. Anybody know?

 

[Lethal1ty17]

i wouldnt think it gets as hot as the combustion (which is over 1800 degrees at its peak) but i could easily see 400 degrees.

 

[xxch4osxx]

Id think it might be higher than that, due to the piston being in contact with the flame front, Im guessing a good 800 degrees maybe a bit more. It also depends on how hard the engine is working as well.

 

[Lethal1ty17]

i doubt it gets that high because a temperature that high would have been mentioned.

example: turbos are known for their high heat and murdering oils because the bearings can get u p over 500 degrees.

if a piston got to more than 500 degrees then every car would be "severe service" and we'd probably know about it by now.